A compiler analyzes an original program, performs optimization and coverts the optimized program into an object code that can be executed by a computer. However, the compiler executes optimization processes only under predetermined conditions and has difficulties performing the most ideal optimizations on various source programs individually.
Optimization of a program is described in, for example, Japanese Patent Application Laid-open No. 2000-35894, Japanese Patent Application Laid-open No. S63-632, Japanese Patent Application Laid-open No. 2010-218367, and Japanese Patent Application Laid-open No. H08-263298.